Dustproof watchcase



Jan. 14, 1941. J. DINHOFER DUSTPROOF WATCHCASE Filed June 10, 1939 TORI Y Patented Jan. 14, 1941 UNITED STATES PATENT OFFICE 1 Claim.

This invention is directed to watches, more particularly to an improved construction of watchcases.

In the construction of watchcases, particularly for use by women, it has been customary to set into such casesjewels of various character. In order to Obtain'the desired brilliancy from the jewels, it was customary in setting the same to first provide openings going all the way i through the watchcase, then setting the diamonds into such openings'and forcing metal from the area adjacent such openings into contact with and over a portion of the jewels to hold them in place. In spite of the best of workmanship, it very frequently happens that minute openings are left at the junction of the jewels and the metal case whereby dust is enabled to creep into the case and eventually find its way into the movement.

In the past it has been proposed to overcome this difficulty by the provision of a lacquer of suitable materials dissolved in organic solvents. Such a lacquer was brushed or sprayed on to the inner surface of the watchcase at the points where the jewels were inserted. This expedient failed to accomplish the desired purpose, in that it was quite difficult to obtain a uniform and complete coating on the inside of the case without making the same too thick in parts to accommodate itself to the watch movement, particularly in the case of small ladies watches. Furthermore, it filled the remainder of the openings in which the jewels were set, and thus prevented the proper reflection and refraction of light, and thereby diminished the brilliancy of the jewels. Furthermore, such a lacquer film actually caught dust and dirt. The application thereof required considerable skill and required special machinery for the purpose which rendered the operation troublesome and expensive.

When a watchcase requires cleaning, it is necessary to remove such a lacquered surface by the use of solvents, which in itself causes additional work and thereafter it is necessary to again apply a lacquer, so that each operator required the special machinery for the purpose.

All of these difiiculties and disadvantages are overcome by the present invention, wherein there is provided a simple and inexpensive means for accomplishing the desired result, whereby the watch movement is fully and adequately protected from the infiltration of dust and dirt, and the brilliancy of the jewels is not at all impaired.

In'practicing the invention, I provide a thin disk of transparent, artificial, film-forming material. This is 'cut to the desired shape and size and inserted within the watchcase at the points to be protected, it being held in place by its own resiliency and stiffness.

In the accompanying drawing, constituting a 6 part hereof and in which like reference characters indicate like parts, Fig. 1 is an enlarged elevational view of a watchcase cover, the view being taken from the inside; Fig. 2 is a vertical cross-sectional view through a, watch considerably more enlarged thanFig. 1, and showing the application of the presentinvention thereto; and Fig. 3 isa plan view of a transparent disk adapted to fit into the watchcase.

As shown in the drawing, there is provided a watchcase I having a cover 2 thereon, said cover comprising a horizontal or top portion 3 and a downwardly extending flange 4. Ears 5 are provided on opposite sides of cover I and there is secured to the same a strap 6 whereby the watch may be held on the wrist of the wearer. In the central portion of the cover is an opening 1 having a crystal-receiving seat or groove 8 in which the usual crystal 9 is held.

A series of openings If] for jewels is provided as desired in the cover 2, such openings extending all the way through the metal. Jewels l l are set therein, and the metal is peened over as shown at l2 in order to hold the jewels securely in place. At the junction I3 of the jewels and openings, minute spaces may be accidently left through which the dust mentioned above may enter.

The inner edge 14 of the cover adjacent to the crystal 9 may be provided with a downwardly depending flange. A thin disk 15 of suitable material such as cellulosic material, including Cellophane, cellulose esters and ethers or artificial resins, and of transparent character is inserted between the flanges 4 and I4 and is pressed into engagement with the underside of cover 2, whereby because of the close fit, a dead air space is formed between the same and portions of the jewels. This minimizes the entry of dust through junctions I 3. At the same time because the jewels are left substantially as free as previously, light without interference is reflected and refracted, thus maintaining the brilliancy of the jewels. Disks I5 are of relatively stiff and self-supporting material and the inner edges 16 thereof are frictionally engaged with flange 14 while the outer edges H thereof are frictionally engaged with the flange 4.

In addition, when the watch movement I8 is within the case as shown in Fig. 2, it fits snugly against the under surface of disk i thereby holding the same in place. The material of disk 15 has a resiliency in addition to rigidity and therefore a very tight fit is obtained between the watch movement and said disk. Furthermore, if the lower edges of the jewels are slightly below he lower surface of the case cover, the resiliency of disk l5 accommodates itself thereto and in spite thereof, a complete and tight fit is obtained.

There are numerous advantages in the present invention in addition to those set forth above, as for example, such disks are inexpensive and may be made up in large quantities in all sizes and types and be stocked in the same manner as crystals are stocked. They are simple to apply in that no special tools whatsoever are required and the ordinary watch repairer is fully capable without any practice of applying the same. When a watch is to be cleaned, it is extremely simple to remove the same and after washing of the watchcase, the same or a new disk may easily be replaced.

Although I have described my invention setting forth a single embodiment thereof, it will be quite apparent to those skilled in the art that my invention is susceptible of many forms within the scope thereof. For example, it is not necessary that the disk I5 be made of the materials mentioned above, but various other materials having the desired properties of toughness, transparency and the like may be substituted therefor. Also, in the watchcase construction a flange I4 is not absolutely essential as by reason of the relative stiffness of the disk and its frictional contact with the outer flange 4 together with the contact of the watch movement, it may be held firmly in its required position to render the case dustproof. It is of course 5 obvious that the form of disk shown in Fig. 3 was intended merely to illustrate the invention and that disks of various sizes, forms and types are also usable. These and other changes may be made in the details of my invention, the scope of which is defined in the claim appended hereto.

What I claim is:

A watch assembly comprising, a watch move ment, a case containing the same, a cover for said case comprising a plate having an opening for receiving and holding a watch crystal, said cover having a continuous marginal portion extending around and completely surrounding the crystal-holding opening, said plate also having a dependent flange adjacent to said opening, the continuous marginal portion being provided with gem-receiving apertures, gems mounted in said apertures, and a thin, flexible transparent sheet of cellulosic material within the cover conforming generally in shape to the marginal portion and closely fitting against and held in contact with the back face of the marginal portion and said flange and covered by and concealed from exterior view by said marginal portion, said sheet closing the inner ends of the gem-receiving apertures and covering the backs of the gems.

JULIUS DINHOFER. 

